Laser oxide removal processes for plating (LORP) is a known technique in which a laser is directed to a substrate to be plated while the substrate is immersed in the plating solution (e.g., an electrolyte solution). However, LORP suffers from certain drawbacks, particularly when used in the UV spectral range. For example, it can be necessary to use a relatively long focal length lens in order to avoid damage to the cell window, which is located in the front part of the tank or electrolytic cell. The use of a long focal length lens results in the laser light having a relatively long distance to travel in the electrolyte before the beam converges, resulting in substantial optical attenuation which, in turn, makes the light less efficient for oxide removal. In contrast, the light incident on a sample that removes the oxide should be maximized, by minimizing losses between the laser output and the region the laser strikes for absorption by the substrate, and increasing the area of oxide removal per unit of incident optical energy/sq-cm.
There remains a need for improved LORP techniques that simplifies existing methods and overcomes disadvantages of current LORP processes.